The present invention relates to automatic transmissions that are mounted on vehicles.
Conventionally, automatic transmissions described in Japanese Patent Application Publication No. JP-A-2004-332803 have been proposed as automatic transmissions that are mounted on vehicles. As shown in FIG. 4, such an automatic transmission includes a hydraulic torque transfer apparatus 80 to which torque from an engine as a driving source is transferred, a speed change mechanism 82 having an input shaft 81 extended into the hydraulic torque transfer apparatus 80, and an oil pump 83 positioned between the hydraulic torque transfer apparatus 80 and the speed change mechanism 82. The hydraulic torque transfer apparatus 80 is provided with a housing 84, which is connected to an output shaft of the engine and is filled with hydraulic oil as a fluid, a torque converter 85 positioned in the housing 84, and a lockup clutch mechanism 86. Note that a cylindrical pump drive shaft 93 for transferring torque from the engine to the oil pump 83 is provided in the housing 84, and an intermediate part of the input shaft 81 (a part in a lateral direction in FIG. 4) is accommodated in the pump drive shaft 93.
The torque converter 85 includes a pump impeller 87 connected to the housing 84, a turbine runner 88 connected to the input shaft 81 so as to face the pump impeller 87, and a stator 89 positioned between the pump impeller 87 and the turbine runner 88. This stator 89 is supported by a substantially cylindrical stator shaft 90, which extends along the lateral direction in FIG. 4, via a one-way clutch 91. A support member 92, such as a bush, for supporting the input shaft 81 rotatably with respect to the stator shaft 90 is provided in the stator shaft 90 at substantially the same position as that of the stator 89 in the extending direction (the lateral direction in FIG. 4). Note that the stator shaft 90 is extended into the speed change mechanism 82, and an intermediate part of the stator shaft 90 in the extending direction is positioned in a space between an inner peripheral surface of the pump drive shaft 93 and an outer peripheral surface of the input shaft 81.
The oil pump 83 is provided with a drive gear 94 connected to the pump drive shaft 93, and a driven gear 95 positioned on the outer peripheral side of the drive gear 94. In the case where the housing 84 rotates by toque transfer from the engine, the oil pump 83 is always driven because the pump drive shaft 93 rotates.